iii) Randomization (Day 0): A computer generated unequal randomized scheme will be used by a research pharmacist in the Johns Hopkins Research Pharmacy to assign patients to riluzole, D-serine, or placebo. The pharmacist making the treatment assignment will be proved with all essential data including patient name and study number, age, weight, and a list of concurrent medications. Subjects already on medications will be equally distributed among treatment groups. Twenty-four subjects each will be randomized to riluzole and D-serine and twelve to placebo. Medications, packaged in look-alike capsules, will be distributed by The Johns Hopkins Research Pharmacy. All medication codes will be retained by the research pharmacist until the completion of the study. All study medication will be double-blind: the Investigators, Study Coordinator and patient/parent will not be aware of the treatment assignment.